<template>
    <!-- 导航栏 -->
    <van-nav-bar
      :title="TypeName"
      left-text="返回"
      left-arrow
      fixed
      placeholder
      z-index="1000"
      @click-left="back"
      @click-right="SearchShow = true"
    >
      <template #right>
        <van-icon name="search" size="20" />
      </template>
    </van-nav-bar>

    <!-- 下拉菜单 -->
    <van-sticky :offset-top="46">
      <van-dropdown-menu>
        <van-dropdown-item @change="TypeToggle" v-model="TypeActive" :options="TypeList" />
        <van-dropdown-item @change="FlagToggle" v-model="FlagActive" :options="FlagList" />
        <van-dropdown-item @change="SortToggle" v-model="SortActive" :options="SortList" />
        <van-dropdown-item @change="ByToggle" v-model="ByActive" :options="ByList" />
      </van-dropdown-menu>
    </van-sticky>

    <!-- 搜索框 -->
    <van-popup v-model:show="SearchShow" position="top">
      <van-search v-model="keywords" placeholder="请输入关键词" @search="search" />
    </van-popup>

    <!-- 下拉刷新 -->
    <van-pull-refresh v-model="refreshing" @refresh="refresh">
      <!-- 加载列表 -->
      <van-list
        v-model:loading="loading"
        :finished="finished"
        :offset="10"
        :immediate-check="false"
        finished-text="没有更多了"
        @load="load"
      >
        <ul class="proul">
          <li v-for="product in list" :key="product.id">
            <router-link :to="`/product/info?id=${product.id}`">
              <van-image
                width="100%"
                height="auto"
                fit="cover"
                :src="product.thumbs_text"
              />
            </router-link>

            <router-link :to="`/product/info?id=${product.id}`">
              <p class="tit">{{product.name}}</p>
            </router-link>
            <div class="price">
              <p>￥{{product.price}} / {{product.unit_text}}</p>
            </div>
          </li>
        </ul>
      </van-list>
    </van-pull-refresh>

    <!-- 返回顶部 -->
    <van-back-top />
</template>

<script setup>
import { onBeforeMount } from "vue";

  const {proxy} = getCurrentInstance()

  let TypeList = reactive([
    {text: '全部分类', value: '0'},
  ]);

  let FlagList = [
    {text: '全部商品', value: '0'},
    {text: '新品', value: '1'},
    {text: '热销', value: '2'},
    {text: '推荐', value: '3'},
  ];

  let SortList = [
    {text: '按上架时间', value: 'createtime'},
    {text: '按价格', value: 'price'},
    {text: '按库存', value: 'stock'}
  ];

  let ByList = [
    {text: '降序', value: 'desc'},
    {text: '升序', value: 'asc'},
  ];

  let TypeActive = ref('0')
  let FlagActive = ref('0')  //标志 1-新品 2-热销 3-推荐
  let SortActive = ref('createtime') //排序 上架时间 价格 库存
  let ByActive = ref('desc')  //desc 降序 asc 升序
  let SearchShow = ref(false) //搜索框的显示
  let keywords = ref('') //搜索关键词
  let TypeName = ref('全部分类') //标题栏上面的分类名称
  
  let list = ref([]) //数据列表
  let page = ref(1)  //分页
  let loading = ref(false) //加载状态
  let finished = ref(false) //是否无更多数据
  let refreshing = ref(false) //下拉刷新

  onBeforeMount(async()=>{
    //初始化分类列表
    let result = await proxy.$GET({
      url:'/product/type'
    })
    result.forEach(e => {
      TypeList.push({text: e.name, value: e.id})
    });
    load()
  })

  //返回上一页
  const back = () => proxy.$router.go(-1)

  //搜索事件
  const search = async () => 
  {
    SearchShow.value = false
    refreshing.value = true

    //触发刷新效果
    refresh()
  }

  //分类切换
  const TypeToggle = async (value) =>
  {
    refreshing.value = true
    TypeActive.value = value
    refresh()

    TypeList.forEach(e => {
      e.value==value && (TypeName.value = e.text)
    });
  }

  //属性切换
  const FlagToggle = async (value) =>
  {
    refreshing.value = true
    FlagActive.value = value
    refresh()
  }

  //排序切换
  const SortToggle = async (value) =>
  {
    refreshing.value = true
    SortActive.value = value
    refresh()
  }

  //升降序切换
  const ByToggle = async (value) =>
  {
    refreshing.value = true
    ByActive.value = value
    refresh()
  }

  //下拉刷新
  const refresh = async () =>
  {
    //可以去掉定时器
    setTimeout(() => {
      //清空查询参数
      page.value = 1
      list.value = []
      finished.value = false
      loading.value = true

      //加载数据方法
      load()
    }, 1000)
  }

  //加载数据方法
  const load = async () =>
  {
    let result = await proxy.$GET({
      url:'/product/index',
      params:{
        pageSize:6,
        page:page.value,
        type:TypeActive.value,
        flag:FlagActive.value,
        sort:SortActive.value,
        order:ByActive.value,
        keywords:keywords.value,
      }
    })
    if(result)
    {
      list.value = list.value.concat(result.data)
      refreshing.value = false
      loading.value = false
      finished.value = !result.has_more
      if(result.has_more)  page.value++
    }

    //请求发送完毕后，加载状态也就完毕了

    //如果没有更多数据了 就说明已经加载到底了....
  }
</script>

<style scoped>
  @import url('/assets/css/ProductIndex.css');
</style>